Azospirillum sp. B510

Azospirillum sp. B510 is a rice endophyte isolated in August 1999 from the surface-sterilized stems of rice plants (Oryza sativa cv. Nipponbare) cultivated in an experimental paddy field in Japan. In addition to being a diazotroph under free-living conditions, B510 was found to have positive motility, and to be capable of degrading plant cell walls. B510 is capable of colonizing internal rice tissues, and inoculation with B510 was shown to promote plant growth under both laboratory and field conditions. It is capable of fixing N(2) in planta. B510 inoculation increases stem number resulting in an increase in seed yield. The genome consists of 1 chromosome and 6 plasmids, 2 of which encode essential genes. There are 280 insertions sequences and at least 2 putative prophages in the genome. Three putative plant hormone-related genes encoding tryptophan 2-monooxytenase (iaaM) and indole-3-acetaldehyde hydrolase (iaaH), which are involved in indole-3-actic acid biosynthesis, and 1-aminocyclopropane-1-carboxylate deaminase (acdS), which reduces ethylene levels, were identified. Moreover, B510 inoculation enhanced disease resistance to virulent rice blast fungus and the bacterial pathogen Xanthomonas oryzae.15 Thus, Azospirillum sp. B510 is likely a beneficial bacterium with agronomic applications (adapted from PMID 20047946). (EBI Integr8)